Whenever Christians go on and on about Heaven or Hell, or predict Jesus is going to return next week and take them home, the larger culture just thinks that we're crazy. All of us. The mistaken Raptures may be worst because they bring ridicule upon us all, since the secular world tends to think of Christianity as monolithic, and these very public mistakes cause even the sympathetic among the secular to ask, "If Christians are wrong about this, what else are they wrong about?"

But a focus on the end of things by Christians of any sort also deforms our faith. Christianity does have beliefs about what happens to us after we die and about the end of time but as N.T. Wright argues, most of us misunderstand those beliefs fundamentally: the Bible is not primarily about how we will go to Heaven when we die. So when we think of Christianity as largely or even mostly Afterlife Insurance, we will most certainly fail to come to grips with the many teachings in both the Old and New (Hebrew and Christian) Testaments about how the faithful should live in this present life.

If we believe Jesus is going to make a special trip to strap jetpacks on us, we aren't forced to care about our brothers and sisters (the heathen who are staying behind to be destroyed anyway), about the creation we've been given, about any of the tasks God assigns us through the prophets and through Jesus himself. If, for example, your primary interest in Israel, like that of Texas pastor John Hagee and his millions of followers, is how you can help promote your version of the End of Time through the Chosen, how can you truly be a Friend of Israel?

Dr. Martin Luther King used to preach that the Gospel both saves our souls and transforms our lives. It demands faith and faithful living, constant prayer—and constant work. When all we're doing is marking time until Jesus comes back to get us, we fail to live as Jesus taught—in love, with courage and compassion, in the world.

The ancient creeds tell us that Jesus will come again in glory to judge the living and the dead, and his kingdom will have no end; and in the Eucharist, we are enjoined to proclaim the mysteries of faith, including that Christ will come again.

I believe that in some very real sense these words are true.

But what exactly does "Jesus will come again" mean and when will it happen?

That is a mystery.

God's time is not calendar time; it's cosmic time. Jesus told us only to be watchful and prepared—advice that goes to the heart of our daily spiritual journey—and more importantly, he said plenty of people would claim to know the whys and whens and wherefores of his return, but that nobody actually does.

Until Jesus comes again in glory, whatever that means, whenever that happens, we are supposed to be about our Father's business.

Maybe somebody should put up a billboard about that.